MW oscillator/ mixer using 2N3819 ? - UK Vintage Radio Repair and Restoration Discussion Forum

Jolly 7 · 5th Mar 2019, 9:40 pm

Does an have a MW oscillator/ mixer circuit based on a 2N3819 that they'd like to share ?
Thanks.

MrBungle · 5th Mar 2019, 11:53 pm

Relatively clever design here: http://kd1jv.qrpradio.com/swbcrx/AMSWBC.HTM

Argus25 · 6th Mar 2019, 5:17 am

Quote:

Originally Posted by MrBungle

Relatively clever design here: http://kd1jv.qrpradio.com/swbcrx/AMSWBC.HTM

I think its reasonable to use a VCO IC as the L/O for a MW radio with a fine & coarse pot to control it, but that is if it is a sine wave oscillator. That circuit uses a square wave output from the 4046 into the mixer. A better IC choice would have been the MAX038 which has a sine wave output.

I have used the MAX038 as the frequency synthesizer in a device for testing and aligning transistor radios, I have posted it before. But the circuit could be lifted out to make a L/O for a MW radio, the sub-circuit is on page 16:

http://worldphaco.com/uploads/The__H...nsanalyser.pdf

MrBungle · 6th Mar 2019, 12:45 pm

Yeah it's not perfect and might end up with a few birdies from harmonic mixing products but it's cheap and easy! I reckon you can possibly work around that with a few minutes in excel playing with the IF and LO frequencies.

5th Mar 2019, 9:40 pm	#1
Jolly 7 Octode Join Date: Feb 2018 Location: Southampton, Hampshire, UK. Posts: 1,063	MW oscillator/ mixer using 2N3819 ? Does an have a MW oscillator/ mixer circuit based on a 2N3819 that they'd like to share ? Thanks.

5th Mar 2019, 11:53 pm	#2
MrBungle Dekatron Join Date: Jun 2016 Location: London, UK. Posts: 3,687	Re: MW oscillator/ mixer using 2N3819 ? Relatively clever design here: http://kd1jv.qrpradio.com/swbcrx/AMSWBC.HTM

6th Mar 2019, 12:45 pm	#4
MrBungle Dekatron Join Date: Jun 2016 Location: London, UK. Posts: 3,687	Re: MW oscillator/ mixer using 2N3819 ? Yeah it's not perfect and might end up with a few birdies from harmonic mixing products but it's cheap and easy! I reckon you can possibly work around that with a few minutes in excel playing with the IF and LO frequencies.